Highlight more Module methods

* lisp/progmodes/ruby-mode.el (ruby-font-lock-keywords): Highlight more
Module methods.

Fixes: debbugs:17216

lisp/ChangeLog

+2014-04-09  Dmitry Gutov  <dgutov@yandex.ru>
+
+	* progmodes/ruby-mode.el (ruby-font-lock-keywords): Highlight more
+	Module methods.  (Bug#17216)
+
 2014-04-08  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* help.el (describe-bindings): Fix buffer handling (bug#17210).

lisp/progmodes/ruby-mode.el

@@ -2065,6 +2065,10 @@ See `font-lock-syntax-table'.")
           "include"
           "module_function"
           "prepend"
+          "private_class_method"
+          "private_constant"
+          "public_class_method"
+          "public_constant"
           "refine"
           "using")
         'symbols))